Kicking down from 2000 RPM in light throttle driving the vehicle will start to surge, if you nail it it clears. Also it will hold in gear sometimes at 3000 RPM on flat ground for some time.

Do we know if the 05's had a modified GM A/T??? What were BMW thinking of??? GM parts in a BMW for cripes sake!

BMW does not make its own transmissions. BMW has used GM-sourced ATs for quite sometime, and they are no more reliable or problematic than other automatics made by ZF. The automatic on a 5-series is no more reliable than one in the X3. The X3 shares its AT with the E46 3-series.

Please explain the bolded part above.......I might be able to tell you why. Kickdown refers to pushing the throttle past the resistance point. I don't see the difference between kickdown and "nailing it" ?

There was a SIB for '04-early '06 models where the 3rd or 4th gear will hold too long while going uphill. The fix is a simple software upgrade to the "hills program". I was one of the first to get the fix and it works fairly well now. I prefer the transmission to hold a bit too long, instead of not holding at all (like my mom's 325i). I live in a hilly area, and to me the gearbox works very well.